Cardiovascular diseases are the first cause of death in developing countries. One of the non-genetic risk factors associated with the development of cardiovascular disease is diet. It has been shown that the incidence of these diseases is directly related to the presence of high blood cholesterol levels that can be caused by a diet with high cholesterol and saturated fat contents.
On the other hand, many studies have shown that oxidation or modification of low density lipoproteins (LDL) triggers the whole atherosclerotic process, in which endothelial activation and activated oxygen species play an important role. Epidemiological studies indicate that the Mediterranean diet is associated with a low incidence of cardiovascular diseases. The most common components of this diet include fruit and vegetables and also olive oil as the main source of fats, all products rich in antioxidants. Results from in vivo and in vitro studies show that antioxidants present in food can counteract the harmful effects of free radicals, preventing LDL oxidation and, therefore, also the atherosclerotic process.
Oxidative stress and the generation of free radicals also play an important part in hepatic and renal diseases, due to the high presence of oxygen in these organs, as well as in the trigger of the inflammatory processes in numerous situations. For this reason, antioxidants in the diet can be crucial to prevent this type of diseases.
Epidemiological studies have demonstrated that UV radiation is the main risk factor in skin cancer. The skin has a defence system to protect against reactive oxygen species produced after exposure to UV radiation, mainly via the enzymatic activities of superoxide dismutase and glutathion peroxidase. A reduction in this defence system, more specifically, in intracellular glutathion levels, produces an increase in the pigmentation, ageing of the skin, induction of apoptosis and can, finally, lead to skin cancer. Hence, supplementation with antioxidants (e.g. vitamin E) has been shown to reverse the situation of oxidative stress induced by UV radiation in human fibroblasts.
Olive oil is a healthy food product rich in oleic acid and antioxidants. Tyrosol and hydroxytyrosol are phenolic compounds obtained from the olive, with a strong antioxidant capacity that has been disclosed both in vivo and in vitro. The possible favorable role of tyrosol and hydroxytyrosol in cardiovascular diseases has been disclosed by some authors who have shown that these compounds reduce the susceptibility of LDL lipoproteins to the in vitro and in vivo oxidation (Masella et al. 2001, Lipids, 36, 1195–1202). It has also been suggested that hydroxytyrosol could reduce lipidic peroxidation in hepatic microsomes in animal studies and that the phenolic antioxidant compounds present in olive oil (tyrosol and hydroxytyrosol) could have a potent antiinflammatory effect.
Tyrosol and hydroxytyrosol are easily oxidizable and, therefore, the use thereof in the form of olive extracts can result in an important proportion of the tyrosol and the hydroxytyrosol being oxidised in the food matrix, which would prevent oxidation of the food. However, both of these compounds would be degraded before entering the organism. It is, therefore, highly beneficial for tyrosol and hydroxytyrosol to reach the organism intact and to exert their strong antioxidant activity therein.
Olive extracts that contain tyrosol or hydroxytyrosol are polar fractions highly soluble in the aqueous phase. A process that would increase the solubility of the antioxidant in an oily phase would be of considerable interest for the food industry. The solubility of tyrosol and hydroxytyrosol can be increased by adding fatty acid chains. In this case, fatty acids can be used that also have beneficial effects on the type of diseases treated in this invention.
Diets have been disclosed such as the Mediterranean diet, which are rich in monounsaturated fats (MUFA) and poor in saturated fats, that have favorable effects on the cardiovascular risk profile (Feldman et al. 1999, Am. J. Clin. Nutr., 70, 953–4). It has been shown that MUFA intake reduces the triglyceride concentration in plasma in healthy volunteers with normal lipid levels (Kris-Etherton et al. 1999; Am. J. Clin. Nutr., 70, 1009–15).
It has also been reported that polyunsaturated fatty acids of the series n-3 (n-3 PUFA), mainly eicosapentanoic acid (EPA) and docosahexanoic acid (DHA), have beneficial effects on the cardiovascular system and on inflammatory processes. The activities disclosed for the n-3 PUFA include antiarrhythmic activity, inhibition of platelet aggregation and reduced plasma lipids and cholesterol levels (Connor et al. 2000, Am. J. Clin. Nutr., 71, 171S–5S).